Secret Mirror Operator

This kubebuilder-based Kubernetes operator copies a Secret to another namespace and synchronizes it with the custom resource SecretMirror.

Reconciliation Logic

1. Get SecretMirror from request.
2. If SecretMirror doesn't exist, just finish the reconciliation. If error occurs, retry later.
3. Get Secret (fromSecret) with SecretMirror's name from fromNamespace Namespace.
4. If Secret (fromSecret) doesn't exist, delete the corresponding Secret (toSecret) if exists. If error occurs, retry later.
5. Create toSecret if not exists.
6. Check if toSecret is managed by secret-mirror-controller.
7. Update toSecret data if data is changed.

Getting Started

1. Install secret-mirror-operator.

   kubectl apply -k github.com/nakamasato/secret-mirror-operator/config/default
   

2. Create src and dst namespace.

   kubectl apply -f config/samples/namespace-dst.yaml,config/samples/namespace-src.yaml

3. Create Secret in src namespace.

   kubectl apply -f config/samples/secret.yaml

4. Create SecretMirror in dst namespace.

   kubectl apply -f config/samples/secret_v1alpha1_secretmirror.yaml

   apiVersion: secret.nakamasato.com/v1alpha1
   kind: SecretMirror
   metadata:
     name: secret
     namespace: dst
   spec:
     fromNamespace: src

5. Check Secret in dst namespace.

   kubectl get secret secret -n dst -o yaml

   apiVersion: v1
   data:
     foo: YmFy
   kind: Secret
   metadata:
     creationTimestamp: "2021-12-30T01:14:26Z"
     name: secret
     namespace: dst
     ownerReferences:
     - apiVersion: secret.nakamasato.com/v1alpha1
       blockOwnerDeletion: true
       controller: true
       kind: SecretMirror
       name: secret
       uid: f1709c26-6497-40b5-84a7-da13c38cf05f
     resourceVersion: "41781"
     uid: 81452942-2562-4f14-be8b-e4c3c856cae6
   type: Opaque

Behaviors

1. Change Secret in dst Namespace manually.

   kubectl patch secret secret -p "{\"data\":{\"manually\": \"$(echo updated | base64 -)\"}}" -n dst
   

   The controller keeps the Secret same as the original Secret.

   kubectl get secret secret -n dst -o jsonpath='{.data}'
   {"foo":"YmFy"}
   

2. Change Secret in src Namespace manually.

   kubectl patch secret secret -p "{\"data\":{\"srcSecret\": \"$(echo updated | base64 -)\"}}" -n src
   

   The controller keeps the Secret same as the original Secret.

   kubectl get secret secret -n dst -o jsonpath='{.data}'
   {"foo":"YmFy","srcSecret":"dXBkYXRlZAo="}
   

3. Delete Secret in dst Namespace.

   kubectl delete sercet dst -n dst
   

   The controller recreates the Secret.

   kubectl get secret secret -n dst -o jsonpath='{.data}'
   {"foo":"YmFy","srcSecret":"dXBkYXRlZAo="}
   

4. Delete Secret in src Namespace.

   kubectl delete secret secret -n src
   

   The controller deletes the Secret in dst Namespace.

   kubectl get secret -n dst
   NAME                  TYPE                                  DATA   AGE
   default-token-wwsmc   kubernetes.io/service-account-token   3      2m19s
   

5. Recreate Secret in src Namespace.

   kubectl apply -f config/samples/secret.yaml
   

   The controller creates a new Secret in dst Namespace.

   kubectl get secret secret -n dst -o jsonpath='{.data}'
   {"foo":"YmFy"}